Queue API is the most complex API in the family of Java Collections Framework. Queue<E> is the base interface for all kind of queues.

• Sub interfaces: BlockingQueue<E>, Deque<E> and BlockingDeque<E>.
• Abstract classes: AbstractQueue<E>.
• Implementation classes:
  • ArrayBlockingQueue<E>
  • ArrayDeque<E>
  • ConcurrentLinkedQueue<E>
  • DelayQueue<E extends Delayed>
  • LinkedBlockingDeque<E>
  • LinkedBlockingQueue<E>
  • LinkedList<E>
  • PriorityBlockingQueue<E>
  • PriorityQueue<E>
  • SynchronousQueue<E>

The following class diagram outlines the hierarchy of Queue API: